It sounds like you're saying earth is special, unusual in some way; that applying the principle of mediocrity is reckless...
I disagree.

Can you show how physics and chemistry on earth differ from the rest of the universe?

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill